1. Field of the Invention
The invention relates to a detection system and mechanism for a currency dispenser which senses the presence of multiple or double bills at any bill location in a series of bills being fed lengthwise in a path of travel, one at a time, from a stacked currency supply to a customer access delivery receptacle of automatic banking equipment.
More particularly, the invention relates to a system and mechanism which gauges the thickness of bills moving in the path of travel, and time averages the gauged measurements along substantially the entire length of the gauged portion of each bill to indicate averaged thickness and to generate a signal indicating whether multiple or double bills, rather than a single bill, are present at any bill location in the series of moving bills.
Also, the invention relates to a detector and system in which the bill thickness gauging is performed mechanically or by light or photosensitive sensor means to generate the signal indicating the occurrence of multiple or double bills, herein called "doubles."
2. Description of the Prior Art
A variety of means have been used in the past for detecting characteristics of paper money or currency bills or other documents being conveyed from place to place in a line or path of travel and fed in a series one by one along the path of travel for counting the bills or documents, for sensing an overlapped relationship of successive documents, or for sensing the presence at any bill location of doubles.
Spring-biased levers, roller switches, photoelectric sensors and other similar devices have been used for these purposes. Examples of bill counters or dispensers are in U.S. Pat. Nos. 3,077,983, 3,168,644, 3,578,315, 3,760,158, 3,767,080, 3,937,453, 3,675,816, and 3,731,916. These prior devices substantially instantaneously generate a signal of the existence of the condition being sensed. In the case of the series of paper money bills being fed, the prior signaling of doubles is triggered immediately whenever the light beam of the photoelectric sensor is attenuated to a degree greater than that representing the thickness of a single bill.
Such a signal may be triggered by the presence of dirt or an inkspot or other dark areas on the bill, or by a folded or small thickened area of the bill anywhere along the bill zone being seen by the sensor, and without the actual presence of doubles. In effect, where currency is being dispensed, such prior detectors may be said to be too sensitive.
Since color, shades of color and variation in thickness of currency thus may trigger such prior photoelectric detectors to produce a doubles signal when doubles actually are not present, problems have arisen which render prior doubles detector devices unsatisfactory for simple, ready, efficient or proper control and handling in automatic banking equipment, for currencies of a number of countries where numerous bill colors for the same bill denomination are used, as well as for handling bills having variable opacity due to variable degrees of color or thickness.
Similar problems also are involved in handling a mixture of new and old paper money bills in such banking equipment, since certain characteristics of old money may differ from those of new money, producing different sensor signals for old as compared to new bills, with one or a given sensor adjustment.
Stated another way, prior doubles detection in currency dispensers has involved looking at a bill at one point; and if it appears thicker, the bill with be rejected as a doubles.
Thus, there exists a need for a doubles detector and system for currency dispensers which permits both new and old bills to be used and intermixed in the currency supply from which currency is dispensed; and also for a detector and system which is not affected by bill color, or changes in color or degree of color, or small bill areas of greater than normal bill thickness.
Further, there exists a need for a doubles detector and system for currency dispensers for automatic banking units which eliminates the stated difficulties or undesirable characteristics encountered in the construction, operation or use of prior devices.